Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2016

Equity Incentive Plans

Assumptions used to determine the fair value of options granted

The assumptions used are shown in the following table.

	2016		2015		2014
Weighted average expected term	5.0 years		6.5 years		6.5 years
Expected volatility	16.0 - 34.3%		16.0 - 37.8%		16.8 - 42.2%
Weighted average volatility	24.3	%	24.7	%	28.3	%
Expected dividends	1.9 - 2.1%		1.6 - 2.1%		1.7 - 2.2%
Weighted average expected dividends	2.1	%	1.7	%	2.1	%
Risk-free rate	0.2 - 2.4%		0.0 - 2.4%		0.0 - 3.0%

Summary of option activity

A summary of option activity for the year ended December 31, 2016 is shown in the following table.

	Number (in 000s)		Weighted average exercise price		Aggregate intrinsic value (in 000s)		Weighted average remaining contractual term (years)
Outstanding as of January 1, 2016	15,716		$	45.81
Granted	3,013		62.84
Exercised	(4,755	)	43.20
Forfeited	(378	)	61.64
Expired	(36	)	64.83
Outstanding as of December 31, 2016	13,560		50.01		$	326,911	6.0
Outstanding, net of expected forfeitures	13,434		49.88		325,668		5.9
Outstanding, exercisable (“vested”)	8,104		42.24		258,367		4.5

Changes in restricted stock units

The changes in restricted stock units are shown in the following table for the year ended December 31, 2016.

	Number (in 000s)		Weighted average grant date fair value
Nonvested as of January 1, 2016	1,839		$	52.86
Granted	360		63.51
Vested	(449	)	39.30
Forfeited	(71	)	59.51
Nonvested as of December 31, 2016	1,679		58.49

Changes in performance stock units

The changes in performance stock awards are shown in the following table for the year ended December 31, 2016.

	Number (in 000s)		Weighted average grant date fair value
Nonvested as of January 1, 2016	930		$	53.27
Granted	520		62.32
Adjustment for performance achievement	(15	)	45.61
Vested	(442	)	45.61
Forfeited	(74	)	61.87
Nonvested as of December 31, 2016	919		61.50